Use Polygon gas oracle (hyperlane-xyz#2965)

### Description

After investigating hyperlane-xyz#2959, I found the following

this is a known problem with Polygon, explanation here
ethers-io/ethers.js#2828 (comment)

Fun fact Asa looked into this once
hyperlane-xyz#771

Here's a discussion it in Foundry, which I found hoping that ethers-rs
folks had ran into this before
foundry-rs/foundry#1703

Foundry fixed this by using the Polygon gas station oracle which seems
to be recommended path
https://github.com/foundry-rs/foundry/pull/3368/files#diff-c89a4bbf7a90da118dcf00c5fe70eba78f8e5d95662bb5f039a353113e95042bR205

There's actually a polygon ethers middleware for this
https://docs.rs/ethers/latest/ethers/middleware/gas_oracle/polygon/struct.Polygon.html

So I (originally) borrowed this code from Foundry
https://github.com/foundry-rs/foundry/blob/master/crates/common/src/provider.rs#L254-L290

Changed to use Middlewares

This also means we can remove our existing janky Polygon logic

### Drive-by changes

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### Related issues

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- Fixes #[issue number here]
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### Backward compatibility

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using this infra tooling?

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### Testing

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What kind of testing have these changes undergone?

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rust/chains/hyperlane-ethereum/src/mailbox.rs

@@ -264,7 +264,7 @@ where
             metadata.to_vec().into(),
             RawHyperlaneMessage::from(message).to_vec().into(),
         );
-        fill_tx_gas_params(tx, tx_gas_limit, self.provider.clone(), message.destination).await
+        fill_tx_gas_params(tx, tx_gas_limit, self.provider.clone()).await
     }
 }
 

rust/chains/hyperlane-ethereum/src/trait_builder.rs

@@ -3,6 +3,9 @@ use std::sync::Arc;
 use std::time::Duration;
 
 use async_trait::async_trait;
+use ethers::middleware::gas_oracle::{
+    GasCategory, GasOracle, GasOracleMiddleware, Polygon, ProviderOracle,
+};
 use ethers::prelude::{
     Http, JsonRpcClient, Middleware, NonceManagerMiddleware, Provider, Quorum, QuorumProvider,
     SignerMiddleware, WeightedProvider, Ws, WsClientError,
@@ -17,7 +20,9 @@ use ethers_prometheus::json_rpc_client::{
 use ethers_prometheus::middleware::{
     MiddlewareMetrics, PrometheusMiddleware, PrometheusMiddlewareConf,
 };
-use hyperlane_core::{ChainCommunicationError, ChainResult, ContractLocator};
+use hyperlane_core::{
+    ChainCommunicationError, ChainResult, ContractLocator, HyperlaneDomain, KnownHyperlaneDomain,
+};
 
 use crate::{signers::Signers, ConnectionConf, FallbackProvider, RetryingProvider};
 
@@ -89,7 +94,7 @@ pub trait BuildableWithProvider {
                     builder = builder.add_provider(weighted_provider);
                 }
                 let quorum_provider = builder.build();
-                self.wrap_with_metrics(quorum_provider, locator, signer, middleware_metrics)
+                self.build(quorum_provider, locator, signer, middleware_metrics)
                     .await?
             }
             ConnectionConf::HttpFallback { urls } => {
@@ -109,7 +114,7 @@ pub trait BuildableWithProvider {
                     builder = builder.add_provider(metrics_provider);
                 }
                 let fallback_provider = builder.build();
-                self.wrap_with_metrics(fallback_provider, locator, signer, middleware_metrics)
+                self.build(fallback_provider, locator, signer, middleware_metrics)
                     .await?
             }
             ConnectionConf::Http { url } => {
@@ -125,15 +130,14 @@ pub trait BuildableWithProvider {
                     &middleware_metrics,
                 );
                 let retrying_http_provider = RetryingProvider::new(metrics_provider, None, None);
-                self.wrap_with_metrics(retrying_http_provider, locator, signer, middleware_metrics)
+                self.build(retrying_http_provider, locator, signer, middleware_metrics)
                     .await?
             }
             ConnectionConf::Ws { url } => {
                 let ws = Ws::connect(url)
                     .await
                     .map_err(EthereumProviderConnectionError::from)?;
-                self.wrap_with_metrics(ws, locator, signer, middleware_metrics)
-                    .await?
+                self.build(ws, locator, signer, middleware_metrics).await?
             }
         })
     }
@@ -174,9 +178,9 @@ pub trait BuildableWithProvider {
         )
     }
 
-    /// Wrap the provider creation with metrics if provided; this is the second
-    /// step
-    async fn wrap_with_metrics<P>(
+    /// Create the provider, applying any middlewares (e.g. gas oracle, signer, metrics) as needed,
+    /// and then create the associated trait.
+    async fn build<P>(
         &self,
         client: P,
         locator: &ContractLocator,
@@ -186,19 +190,20 @@ pub trait BuildableWithProvider {
     where
         P: JsonRpcClient + 'static,
     {
-        let provider = Provider::new(client);
+        let provider = wrap_with_gas_oracle(Provider::new(client), locator.domain)?;
+
         Ok(if let Some(metrics) = metrics {
             let provider = Arc::new(PrometheusMiddleware::new(provider, metrics.0, metrics.1));
             tokio::spawn(provider.start_updating_on_interval(METRICS_SCRAPE_INTERVAL));
-            self.wrap_with_signer(provider, locator, signer).await?
+            self.build_with_signer(provider, locator, signer).await?
         } else {
-            self.wrap_with_signer(provider, locator, signer).await?
+            self.build_with_signer(provider, locator, signer).await?
         })
     }
 
     /// Wrap the provider creation with a signing provider if signers were
-    /// provided; this is the third step.
-    async fn wrap_with_signer<M>(
+    /// provided, and then create the associated trait.
+    async fn build_with_signer<M>(
         &self,
         provider: M,
         locator: &ContractLocator,
@@ -208,7 +213,7 @@ pub trait BuildableWithProvider {
         M: Middleware + 'static,
     {
         Ok(if let Some(signer) = signer {
-            let signing_provider = build_signing_provider(provider, signer)
+            let signing_provider = wrap_with_signer(provider, signer)
                 .await
                 .map_err(ChainCommunicationError::from_other)?;
             self.build_with_provider(signing_provider, locator)
@@ -224,7 +229,7 @@ pub trait BuildableWithProvider {
         M: Middleware + 'static;
 }
 
-async fn build_signing_provider<M: Middleware>(
+async fn wrap_with_signer<M: Middleware>(
     provider: M,
     signer: Signers,
 ) -> Result<SignerMiddleware<NonceManagerMiddleware<M>, Signers>, M::Error> {
@@ -237,3 +242,36 @@ async fn build_signing_provider<M: Middleware>(
     let signing_provider = SignerMiddleware::new(provider, signer);
     Ok(signing_provider)
 }
+
+fn build_polygon_gas_oracle(chain: ethers_core::types::Chain) -> ChainResult<Box<dyn GasOracle>> {
+    let gas_oracle = Polygon::new(chain)
+        .map_err(ChainCommunicationError::from_other)?
+        .category(GasCategory::Standard);
+    Ok(Box::new(gas_oracle) as Box<dyn GasOracle>)
+}
+
+/// Wrap the provider with a gas oracle middleware.
+/// Polygon and Mumbai require using the Polygon gas oracle, see discussion here
+/// https://github.com/foundry-rs/foundry/issues/1703.
+/// Defaults to using the provider's gas oracle.
+fn wrap_with_gas_oracle<M>(
+    provider: M,
+    domain: &HyperlaneDomain,
+) -> ChainResult<GasOracleMiddleware<Arc<M>, Box<dyn GasOracle>>>
+where
+    M: Middleware + 'static,
+{
+    let provider = Arc::new(provider);
+    let gas_oracle: Box<dyn GasOracle> = {
+        match domain {
+            HyperlaneDomain::Known(KnownHyperlaneDomain::Polygon) => {
+                build_polygon_gas_oracle(ethers_core::types::Chain::Polygon)?
+            }
+            HyperlaneDomain::Known(KnownHyperlaneDomain::Mumbai) => {
+                build_polygon_gas_oracle(ethers_core::types::Chain::PolygonMumbai)?
+            }
+            _ => Box::new(ProviderOracle::new(provider.clone())),
+        }
+    };
+    Ok(GasOracleMiddleware::new(provider, gas_oracle))
+}

rust/chains/hyperlane-ethereum/src/tx.rs

@@ -9,9 +9,7 @@ use ethers::{
 };
 use ethers_contract::builders::ContractCall;
 use ethers_core::types::BlockNumber;
-use hyperlane_core::{
-    utils::fmt_bytes, ChainCommunicationError, ChainResult, KnownHyperlaneDomain, H256, U256,
-};
+use hyperlane_core::{utils::fmt_bytes, ChainCommunicationError, ChainResult, H256, U256};
 use tracing::{error, info};
 
 use crate::Middleware;
@@ -73,7 +71,6 @@ pub(crate) async fn fill_tx_gas_params<M, D>(
     tx: ContractCall<M, D>,
     tx_gas_limit: Option<U256>,
     provider: Arc<M>,
-    domain: u32,
 ) -> ChainResult<ContractCall<M, D>>
 where
     M: Middleware + 'static,
@@ -91,16 +88,6 @@ where
         // Is not EIP 1559 chain
         return Ok(tx.gas(gas_limit));
     };
-    let max_priority_fee = if matches!(
-        KnownHyperlaneDomain::try_from(domain),
-        Ok(KnownHyperlaneDomain::Polygon)
-    ) {
-        // Polygon needs a max priority fee >= 30 gwei
-        let min_polygon_fee = U256::from(30_000_000_000u64);
-        max_priority_fee.max(min_polygon_fee.into())
-    } else {
-        max_priority_fee
-    };
     // Is EIP 1559 chain
     let mut request = Eip1559TransactionRequest::new();
     if let Some(from) = tx.tx.from() {

rust/chains/hyperlane-ethereum/src/validator_announce.rs

@@ -86,7 +86,7 @@ where
             announcement.value.storage_location,
             serialized_signature.into(),
         );
-        fill_tx_gas_params(tx, tx_gas_limit, self.provider.clone(), self.domain.id()).await
+        fill_tx_gas_params(tx, tx_gas_limit, self.provider.clone()).await
     }
 }